[mm PATCH v3 12/23] arch/nios2: Add option to skip DMA sync as a part of map and unmap
From: Alexander Duyck <hidden>
Date: 2016-11-10 17:36:33
Also in:
lkml, netdev
Subsystem:
nios2 architecture, the rest · Maintainers:
Dinh Nguyen, Simon Schuster, Linus Torvalds
This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to avoid invoking cache line invalidation if the driver will just handle it via a sync_for_cpu or sync_for_device call. Cc: Ley Foon Tan <redacted> Signed-off-by: Alexander Duyck <redacted> --- arch/nios2/mm/dma-mapping.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/arch/nios2/mm/dma-mapping.c b/arch/nios2/mm/dma-mapping.c
index d800fad..f6a5dcf 100644
--- a/arch/nios2/mm/dma-mapping.c
+++ b/arch/nios2/mm/dma-mapping.c@@ -98,13 +98,17 @@ static int nios2_dma_map_sg(struct device *dev, struct scatterlist *sg, int i; for_each_sg(sg, sg, nents, i) { - void *addr; + void *addr = sg_virt(sg); - addr = sg_virt(sg); - if (addr) { - __dma_sync_for_device(addr, sg->length, direction); - sg->dma_address = sg_phys(sg); - } + if (!addr) + continue; + + sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + + __dma_sync_for_device(addr, sg->length, direction); } return nents;
@@ -117,7 +121,9 @@ static dma_addr_t nios2_dma_map_page(struct device *dev, struct page *page, { void *addr = page_address(page) + offset; - __dma_sync_for_device(addr, size, direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + __dma_sync_for_device(addr, size, direction); + return page_to_phys(page) + offset; }
@@ -125,7 +131,8 @@ static void nios2_dma_unmap_page(struct device *dev, dma_addr_t dma_address, size_t size, enum dma_data_direction direction, unsigned long attrs) { - __dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + __dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); } static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
@@ -138,6 +145,9 @@ static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg, if (direction == DMA_TO_DEVICE) return; + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + return; + for_each_sg(sg, sg, nhwentries, i) { addr = sg_virt(sg); if (addr) --
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